Block copolymers have been developed rapidly within the recent past, the starting monomers usually being monoalkenyl arenes such as styrene or alpha-methylstyrene and conjugated dienes such as butadiene and isoprene. A typical block copolymer of this type is represented by the structure polystyrene-polybutadiene-polystyrene (SBS). When the monoalkenyl arene blocks comprise less than about 55% by weight of the block copolymer, the product is essentially elastomeric. Moreover, due to the peculiar set of physical properties of such a block copolymer it can be referred to more properly as a thermoplastic elastomer. By this is meant a polymer which in the melt state is processable in ordinary thermoplastic processing equipment but in the solid state behaves like a chemically vulcanized rubber without chemical vulcanization having been effected. Polymers of this type are highly useful in that the vulcanization step is eliminated and, contrary to vulcanized scrap rubbers, the scrap from the processing of thermoplastic elastomers can be recycled for further use.
These block copolymers, because of their hydrocarbon composition, are non-polar in character. This non-polarity presents problems in adhesion, paintability, printability, and other performance requirements dependent on surface polarity. One means to achieve polarity is to blend polar resins with the block copolymer. However, not all polar resins are technologically compatible with the above-described block copolymers. Further, not all resins exhibit the desired characteristics for certain critical applications. A blend of block copolymers and a certain acrylic ester has now been found that not only exhibits improved adhesion, paintability and printability, but also forms translucent blends which have good rubbery characteristics and respectable tensile strengths.